Expanding gate valve assembly

Abstract

An expanding gate valve which includes a reciprocating gate supporting at least one floating segment supported on one side thereof with a wedging means between the gate and the segment for wedging movement of the segment transverse to the fluid flow path and further wedging the segment against a valve body seating surface upon reciprocating movement of the gate in selective response to valve stem movement so as to seal the fluid flow passageway from the valve body cavity selectively in a fluid flow closed position or in a fluid flow open position of the valve, wherein the floating segment comprises a first wedging surface configured to coact with the gate and a second wedging surface to coact with the valve seating surface.

I claim: 
     
       1. A valve comprising: a valve body having a body cavity with a fluid flow passageway therethrough defining a fluid flow path intersecting the body cavity, the valve body having a valve seating surface located on one side of the valve body facing the body cavity and surrounding the fluid flow passageway;   a flow control means disposed in the body cavity for selectively closing and opening the fluid flow passageway, the flow control means comprising: a gate;   a stem connected to the gate for selectively moving the flow control means; and   a floating segment having a sealing surface configured to wedge against the valve seating surface, the floating segment supported on the gate with a first wedging means between the gate and the segment for causing a wedging movement of the segment in a direction transverse to the fluid flow path and further causing wedging of the sealing surface of the segment against the valve seating surface upon a reciprocating movement of the gate in one direction in selective response to valve stem movement so as to close the fluid flow passageway.     
     
     
       2. The valve of claim 1 wherein the segment further comprises a fluid flow conduit therethrough alignable with the fluid flow passageway. 
     
     
       3. The valve of claim 2 wherein the flow control means comprises a second wedging means between the gate and the segment, said second wedging means disposed in a direction opposite to the first wedging means for causing a wedging movement of the segment in a direction transverse to the fluid flow path and further causing wedging of the sealing surface of the segment against the valve seating surface upon a reciprocating movement of the gate in the opposite direction in selective response to valve stem movement so as to open the fluid flow passageway. 
     
     
       4. A valve comprising: a valve body having a body cavity with a fluid flow passageway therethrough defining a fluid flow path intersecting the body cavity, the valve body having a valve seating surface located on one side of the valve body facing the body cavity and surrounding the fluid flow passageway;   a flow control means disposed in the body cavity for selectively closing and opening the fluid flow passageway, the flow control means comprising: a gate having a first face on a side of the gate facing the fluid flow path; and   a floating segment disposed on the gate, the floating segment comprising: a sealing surface on one side of the segment to wedge against the valve seating surface for closing the fluid flow passageway; and   a gate-contacting face of the segment facing the first face of the gate, the gate-contacting face of the segment and the first face of the gate together configured to comprise a first wedging means for causing a wedging movement of the segment in a direction transverse to the fluid flow path; and       a valve operator means for selectively reciprocating the flow control means to a flow closed position or to a flow open position, the valve operator means comprising: a stem having a stem axis extending transversely to the fluid flow path, the stem connected to the flow control means by a connecting means that provides reciprocating motion of the flow control means.;   a valve operator connected to the stem for selectively moving the stem; and   a stem moving means associated with the valve operator and the stem, said stem moving means causing the stem to selectively move in a sequence of steps that ends with only axial motion in response to movement of the valve operator in one direction, and begins with only axial motion in response to movement of the valve operator in another direction, whereby movement of the valve operator in said one direction causes the gate to be loaded with an axial force by the stem thereby causing the first wedging means to move the segment outwardly away from the gate and further causing the sealing surface of the segment to wedge against the valve seating surface so as to sealingly close the fluid flow passageway, and movement of the valve operator in said another direction causes the gate to be substantially unloaded of axial force from the stem thereby causing the floating segment to collapse towards the gate and move together with the gate during a pre-determined interval of movement of the flow control means to open the fluid flow passageway.       
     
     
       5. The valve of claim 4 wherein the floating segment further comprises a fluid flow conduit therethrough alignable with the fluid flow passageway in the valve body. 
     
     
       6. The valve of claim 5 wherein the flow control means further comprises a second wedging means between the gate and the floating segment, said second wedging means disposed in a direction opposite to the first wedging means, whereby further movement of the valve operator in said another direction causes the gate to be loaded with an axial force by the stem thereby engaging only the second wedging means and causing the floating segment to move outwardly away from the gate and further causing the floating segment to wedge against the valve seating surface in a fluid flow open position of the flow control means.